Downloadable spreadsheet calculator for solar, power use, and battery sizingYou really need to calculate your power usage before sizing anything 12v electrical for your TT. From those numbers you can choose amount of battery storage and what charging methods are best for your situation.
FWIW, I have 235 W of solar panel and it takes care of all my needs except air conditioning and microwave. It also runs my 120V dorm fridge when away from shore power. I use a 1000 W Xantrex inverter and that handles all of my 120 V needs.
Replacing incandescent (standard) interior lighting over to LED lighting is one of the best modifications you can do to save power, they operate at 1/5 the draw of typical incandescents.